3OO MICROBIOLOGY OF MILK AND MILK PRODUCTS. 



EXTERIOR or Cow's BODY. The nature of the cow's coat and the 

 condition under which she is normally kept favor the accumulation of dust 

 and bacteria upon her body. Unless special care is taken to keep the 

 cow's body free from dust, the organisms which fall into the milk from 

 this source at milking-time will constitute one of the most important 



FIG. 74. Colonies developing in agar plate held for ten seconds in position of milk \ ail 

 after udder was brushed gently with the hand. (Original.) 



sources of contamination. The importance of this source of contami- 

 nation may be recognized when we see what large numbers of micro- 

 organisms may be carried by small particles of dust or an individual 

 cow hair. 



The importance of this source of contamination depends very largely 

 upon the conditions under which the cows are kept and the care exercised 



